8.10 Conclusion

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Today’s TDM systems use a variety of techniques to maximize throughput, facilitate network management, and restore transmission facilities. Properly equipped multiplexers and cross-connect systems, for example, can provide substantial savings on the cost of private networking by using bandwidth more efficiently to minimize the number of lines needed and by reconfiguring lines and rerouting traffic on a scheduled or event-driven basis to accommodate changing needs or take advantage of the most economic services available. All of this, in turn, reduces the payback period of the initial investment in such systems.

Successful implementation of a TDM network hinges on the capabilities of the equipment to monitor for errors and delays and recover from fault conditions, as well as to prioritize and manage voice and data. In this way, the diverse application needs of the organization can be addressed properly without compromising the communications budget. Toward that end, the equipment should provide efficient interconnectivity of public and private network elements so the organization can leverage existing carrier offerings and benefit from new ones, while extending the reach of private facilities economically through the public network.

But the decades old reign of the TDM architecture may be headed for an end. Every carrier has a strategy in place to migrate its base of corporate customers from TDM networks to fast-packet networks. Instead of supporting voice and data over separate networks or trying to squeeze them into outmoded time slots, carriers want to run all traffic types over a unified fast-packet network, preferably an IP network because of its lower cost and global availability.

To encourage this migration, carriers are educating organizations about the benefits of so-called “IP convergence,” which lowers costs, simplifies the network, and allows customers to choose network infrastructures based on applications, instead of becoming locked into artificial technology constraints and specific vendor offerings. IP convergence supports productivity-enhancing applications such as multimedia to the desktop and unified messaging. It also supports cost-effective, all-distance connections and centralizes and simplifies security management. Finally, the ability to access IP through existing access services optimizes price and performance for each enterprise location.

Hardware vendors, too, are looking at how to migrate customers away from TDM-based products toward IP-based systems. All the major PBX manufacturers, for example, offer IP adjunct systems for connection to their conventional PBXs, enabling organizations to take advantage of IP for voice calling. These same vendors, sensing a change in customer purchasing patterns, also offer full-blown IPbased PBX systems. In fact, vendors are spending more for the development of IP systems than for conventional PBXs. Customers replacing or upgrading existing PBXs, or buying one for the first time, are more inclined to go with IP-based solutions.

Even wireless technologies—specifically 802.11b, also known as Wi-Fi—that started out as a way to extend the reach of Ethernet LANs without having to install new wiring to accommodate growth or keep up with organizational changes are now being extended with new standards to support voice and video. Local exchange carriers and interexchange carriers, too, are looking into Wi-Fi as a value-added service to complement their 2.5/3G data offerings such as general packet radio service (GPRS), which offers “always-on,” higher capacity, Internet-based content and packet-based data services, supporting Internet browsing, e-mail on the move, visual communications, multimedia messaging, and location-based services. The use of these wireless technologies is giving telecom and IT managers more flexibility in meeting corporate communications needs and can offer more opportunities for cost savings.

But the adoption of fast-packet solutions will be evolutionary, not revolutionary.-There is simply too much capital tied up in TDM infrastructures to permit change to occur too fast. Furthermore, sales of PBXs, multiplexers, channel banks, and cross-connect systems continue at a brisk pace, which has the effect of prolonging reliance on TDM. Such systems, including multiplexers and channel banks, even incorporate router functionality with optional plug-in modules, thereby extending the useful life of TDM products. In terms of management, SNMP has bridged the gap between these legacy systems and the newer fast-packet infrastructures, which contributes to the slower pace of migration.



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LANs to WANs(c) The Complete Management Guide
LANs to WANs: The Complete Management Guide
ISBN: 1580535720
EAN: 2147483647
Year: 2003
Pages: 184

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